It has been recognized, and especially in the past decade that solid waste disposal is a matter of genuine environmental concern. In particular, landfill sites which have been in previous use have in many instances approached complete filling. Accordingly, the opening of additional landfill sites for disposal of various waste products has been necessary. This exhaustion of available landfill space for various waste components has resulted in higher disposal fees. Moreover, transportation costs for disposal of such waste products have increased because of the longer distances to be travelled to revised landfill sites
In addition to the increase in economic costs for disposal waste products, solid waste reduction programs have been evolving from voluntary status to one of legal obligation, based upon federal, state and local legislation to reduce solid waste disposal difficulties. Increased legislation in that regard is likely to compel further reduction of solid waste volumes.
In view of the above difficulties of disposal of solid waste products, recycling and salvage of at least some components of scrap materials has been desirable. However, certain difficulties have been associated with the separation and salvage of various individual components of laminated products, and particularly laminated products produced by a reaction injection molding process, such as are used in the automobile industry.
Reaction injected molds are utilized in the automobile and other industries to produce soft foam products having a substrate usually comprising one or more thermoplastic resins to provide rigidity, a skin which may be a vacuum formed or cast material, for example cast vinyl, to provide appearance and texture, and a foam interspersed therebetween to provide softness to the product. This particular form of product has created substantial difficulties in the industry in regard to separation and salvage of the individual components. Effective separation and salvage may yield reusable plastic resins and also perhaps potentially useable foam components.
Various techniques have been suggested for separating various types of polymeric scrap materials. For example, U.S. Pat. No. 3,843,060 to Colburn discloses a process for the reclamation of fabric-supported thermoplastic sheet scrap. The process involves granulating the fabric-supported thermoplastic sheet into a particulate mixture containing thermoplastic chips, chopped fabric, lint and fly. This mixture is fed into a cyclone wherein the lint and fly are separated, leaving a second mixture comprised primarily of thermoplastic chips and chopped fabric. Finally, this second mixture is separated into thermoplastic chip and chopped fabric components utilizing a specific gravity air separator.
U.S. Pat. No. 4,981,876 to Grimmer discloses a process for separating vinyl skin from a foam backing and recovering the separated components by granulating the composite into small chips and subjecting the chips to flotation separation.
Various "wet" processes require additional drying and other steps, and would increase engineering difficulty, costs, and create yet other problems, such as plasticization, solution disposal etc.